LayoutTests/http/tests/cookies/private-cookie-storage.html

<script src="resources/cookies-test-pre.js"></script>
<script>
description("This test checks that cookies set from a Set-Cookie header in private browsing mode are stored in the same cookie storage as cookies set with document.cookie.");

debug("Cookies before setting (should be empty):" + document.cookie);

document.cookie = "key1=value1";
debug("Cookies before enabling private browsing (should be key1=value1):" + document.cookie);
testCookies("key1=value1");

if (window.testRunner) { testRunner.setPrivateBrowsingEnabled(true); }

debug("Cookies after enabling private browsing (should be empty):" + document.cookie);
testCookies(""); // We're using a different cookie storage now.  key1=value1 is still in the default cookie storage.
document.cookie = "key2=value2";
debug("Cookies after setting in private browsing (should be key2=value2):" + document.cookie);
testCookies("key2=value2");
clearCookies();

if (window.testRunner) { testRunner.setPrivateBrowsingEnabled(false); }

debug("Cookies after disabling private browsing (should be key1=value1):" + document.cookie);
testCookies("key1=value1");

</script>
<script src="resources/cookies-test-post.js"></script>